Fuel tank cap



FIG. 1 is a perspective view of a fuel tank cap showing my new design;

FIG. 2 is a left elevation view thereof;

FIG. 3 is a front elevation view thereof;

FIG. 4 is a top plan view thereof;

FIG. 5 is a rear elevation view thereof;

FIG. 6 is a bottom plan view thereof; and,

FIG. 7 is a right elevation view thereof.

The broken line showing of environment is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a fuel tank cap, as shown and described. 